Slip ring arrangement



1952 R. G. LE TOURNEAU ET'AL 2,623,183

SLIP RING ARRANGEMENT 2 SHEETS-SHEET 1 Filed Sept. 24, 1949 INVENTOR.R057. 6. LETOURNEAU AGEN & CHARLES C. R05 J X9. 7044;

G r 5 H b 3 a m 9 0 A k v n m w a 2 K v 4% 6 6 M}- 3 w m m a H N/ r v Wv 2 4 M. 7 5 r% a N Dec. 23, 1952 R. 6. LE TOURNEAU EI'AL 2,623,188

SLIP RING ARRANGEMENT Filed Sept. 24, 1949 2 SHEETSSHEET 2 INVENTOR.

R057? 6. LEToz/R/vmu & CHARLES C. R05

Patented Dec. 23, 1952 UNITED STATES PATENT OFFICE SLIP RING ARRANGEMENTApplication September 24, 1949, Serial No. 117,582

18 Claims.

This invention relates generally to a device for connecting an externalelectric circuit with rotor windings of a dynamo-electric machine, andmore particularly to an arrangement of contact between a stationarybrush holder and slip rings mounted on a rotor shaft.

The primary object of this invention is to provide a unique arrangementwhereby the totor slip rings are each provided with a radial face forcontact with a radial face of its corresponding brush, and all theradial surfaces are held in contact by common pressure means.

An additional object is to provide a brush holder for cooperation withradial slip rings wherein the brushes and slip rings will remain incontact regardless of the vibration of the rotor or wear of the brushes.

A further object is to provide a holder for using a continuous ringcarbon brush in this slip ring arrangement.

Another object is to provide a means of attaching slip rings to a rotorshaft in a secure but easily removable manner.

Yet another object is to provide a means for supporting a brush holderwhich permits removal and replacement of brushes without manipulation ofscrews, clamps, or other securing devices and affords virtuallyinstantaneous replacement. 7

A still further object is to provide a brush holder and slip rings whichin combination virtually surround the brushes, so that the brushes andthe metal surfaces they contact are free from exposure to grit, dust,and foreign matter, and the metal surfaces not subject to oxidation ason conventional devices where a brush with relatively small surfacecooperates with a slip ring of a much larger surface.

Other features of novelty will become apparent from a perusal of thefollowing specification and claims.

In the drawing:

Fig. 1 represents a sectional elevation of this slip ring arrangementinstalled on a rotor shaft.

Fig. 2 is an end view of the brush end of the rotor shaft showing theinstallation thereon of one slip ring and its retainer bushing.

Fig. 3 is an elevation view of one brush holder with its continuous ringbrush installed.

Fig. 4 is an end view of the combination insulator and spring retainerused with this invention. 7

Referring now more particularly to the characters or reference on thedrawing, in Fig. 1 this slip ring arrangement installed on a rotor shaftl is seen to consist basically of an assembly including a pair ofopposed aluminum brush holders 2 and 2a which include a recessed portion3 to receive a split continuous ring carbon brush 4, brass or bronzeslip rings 5 and 5a which are mounted on tapered steel collars 6 and-6a, and a pair of studs 1 for securing the stationary part of theassembly against rotation With the shaft.

Examining one of the brush holders more in detail, in Fig. 3, it is seento include in addition to recess 3, an enlarged center opening 8,diametrically opposed ears 9 which include a bore l0 and counterbore II, radially drilled holes I2 and I3 for receiving respectively a holdingscrew l4 and a terminal screw [5. The other brush holder 2a is identicalto holder 2 except its bore l0 and counterborell are sufficiently largerto receive an insulating bushing It. This bushing is shown in Fig. 4 andFig. 1 and includes a spring seat counterbore IT, a central bore [8 of aslightly larger diameter than stud l, and an external shoulder l9joining its smaller circumference 20 with its outer circumference 2|.

The revolving. portion of this device is seen from Fig. 1 to include thetwo slip rings and their collars installed on rotor shaft 1. An assemblyof one collar and ring will be seen in Fig. 2 to consist of slip ring 5pressed onto tapered collar 6 which surrounds shaft I. Between themating tapered surfaces 22 of the slip ring and 23 of the collar thereis installed a thin insulator 24 which here assumes a circular formexcept.

for its ends 25 which are bent over the edges of slot 26 of the collarto permit direct passage of return lead 21 from its position inlongitudinal groove 28 of the shaft I. A similar groove 29 is machinedinto the shaft in a diametrically opposed position. Groove 28 inaddition to providing passage for return lead 21 provides a means forpreventing relative rotation of the shaft I and collar 6a by engaging asmall projection 31a of the latter, in the same manner as shown forgroove 29. and projection 3|.

- In the assembly of both slip ring-collar groups on the shaft, eachgroup is spaced and insulated from the other by an insulatingwasher 32and both groups are held securely in placeby lock nut 33 which bytightening onto threads 34'of shaft 1 causes both groups and spacer 35to secure against shoulder 36 of the shaft. This spacer includesdiametrically opposed lead openings 31 and is employed only in caseswhere the shoulder 36 is too close to lock nut 33 to permit passage ofleads 21 and 30 from their respective grooves 28 and 2% in the shaft.Lead 3% carries the input current to windings (not shown) of a rotoremploying this slip ring arrangement while lead 2'! provides for thereturn thereof. Separate external supply current leads (not shown) aresubsequently attached to terminal screw it of each brush holder.

Exciter current for the field windings on a generator rotor, or D. C.current for a wound rotor machine is introduced thru terminal screw l ofbrush holder 2a. This direct current is conducted from the brush holderthru brush =3 into slip ring 5a which is directly attached to lead whichcarries current to the rotor windings thru spacer (if used). Since therecess 3 of the brush holder surrounds brush 4 on two sides, and sincethe radial surface of slip ring 5a is in direct contact with brush 4 andthe horizontal surface of the slip ring is in close juxtaposition withthe brush, there is practically no metal surface with which the brushcomes in contact that is exposed to dirt or foreign matter, or subjectto oxidation. These factors which are known to be detrimental to brushlife have thus been virtually eliminated by the construction of thisinvention. The return lead 21 connects the field windings at theopposite end thereof from lead 30, and by way of groove 28 connects toslip ring 5 and from there thru the brush and holder 2 to its terminalIE.

The brush holders, brushes, and slip rings are all securely held inoperative contact by the pressure of springs 39. These springs are shownin this embodiment to be located at the diametrically opposed ears 9 andseated in counterbore l l of brush holder 2 and counterbore ll ofinsulated bushing 16 which is itself secured in the enlarged bore Idaand counterbore I l a of holder 2a. The shoulder [9 of bushing l8prevents the bushing from being forced thru the holder under the springpressure. The brush holders 2 and 2a are secured against rotation by thestuds i which pass thru corresponding bores Ill and ma of the holdersand bore [8 of the bushing; studs 1 further act as a guard to preventsprings 35 from jumping out of alignment during installation,replacement of brushes, etc.

In operation the use of holding screw it is optional, as it has beenfound advantageous to permit the brush 4 to turn freely within recess 3of the brush holder. What actually takes place in this situation is thatthe centrifugal force of the rotor causes the two sections of thesplitcontinuous ring brush 4 to be forced out and drag at its 0. D. againstthe brush holder; this action, together with the pressure of springs 39,forces the radial faces of the brush, brush holder and slip ring alltogether, and results in a creeping motion of the brush around therecess 3. This creeping motion is desirable as it distributes the wearevenly about the brush to compensate for any irregularities of thecontacting radial surfaces and for unequal spring pressure.

It should be understood that brushes 5 have the same operational effectas if they were a continuous ring. They are, however, split as at 48- tofacilitate installation. When it is desired to replace the brushes on amachine employing this arrangement, it is merely necessary to pull oneof the holders, for instance 2, toward the other holder 2a withsufficient force to overcome the pressure of springs 39. This willusually cause the brushes to drop from the slip ring when theirsupporting holder has thus been removed. In other cases a slightmanipulation of the holder or brush will permit it to fall clear of itshousing. Comparable ease is experienced in installing the brushes whichis simply the reverse of the removal: the brush holder is pulled backagainst the springs and the brush installed in two pieces. Thisinstallation is noticeably faster and simpler than the delicateinstallation and adjustment required on most conventional machines.

From. the foregoing description, it will be readily seen that we haveproduced such an implement as substantially fulfills the objects of theinvention as set forth herein.

While this specification sets forth in detail the present and preferredconstruction of this slip ring arrangement, still in practice suchdeviations from such detail may be resorted to as do not form adeparture from the spirit of the invention as described in the appendedclaims.

Having thus described the invention, the following is claimed as new anduseful and upon which Letters Patent is desired:

1. A slip ring arrangement for dynamo-electric machines including arotor shaft and rotor windings, comprising: a radial face slip ringsupported on the shaft, a brush holder spaced from said slip ring, and acircular brush surrounding said shaft and disposed between said slipring and said brush holder and said brush being free to move both withrespect to said slip ring and with respect to said brush holder.

2. A slip ring arrangement for dynamo-electric machines including arotor shaft and rotor windings, comprising: a pair of radial face sliprings supported on the shaft, a pair of brush holders spaced from saidslip rings, semi-circular brushes disposed between said slip rings andsaid brush holders, and a common means operating between the brushholders to urge said brushes into contact with said slip rings.

3. A slip ring arrangement for dynamo-electric machines including arotor shaft and rotor windings, comprising: a pair of radial face sliprings spaced apart longitudinally on the shaft, a pair of generallycircular brush holders surrounding the shaft between the slip rings, acontinuous ring brush disposed between each adjacent slip ring and brushholder and means between said brush holders to cause forcible engagementof said brushes and slip rings, said means being circumferentiallyspaced compression springs.

4. A slip ring arrangement for dynamo-electric machines including arotor shaft and :rotor windings, comprising: a pair of radial face sliprings spaced apart longitudinally on the shaft, a pair of generallycircular brush holders surrounding the shaft between the slip rings, anannular recess in the radial face of each brush holder on the sideadjacent its corresponding slip ring, a continuous ring brush insertedin said recess and free to move radially with respect to .said sliprings and said brush holders, the radial face of said brush adapted toforcibly engage the radial face of said corresponding slip ring.

5. A slip ring arrangement for dynamo-electric machines including arotor shaft and rotor windings, comprising: a pair of radial face sliprings spaced apart longitudinally on the shaft, said slip rings beingL-shaped in cross section,'a pair of generally circular brush holderssurrounding the shaft, said brush holders being L-shaped in crosssection, each brush holder being associated with one slip ring to form apair of corresponding elements, the L-shaped sections .of each elementof the pair cooperating with the other to form an enclosure ofbox-shaped cross section,

andbrush of box-shaped cross section inserted in said enclosure.

6. A' slip ring arrangement for dynamo-electric machines including arotor shaft, rotor winding, and a stationary frame, comprising: a pairof cylindrical slip rings with a radial face and a horizontal surface; agenerally circular brush holder, including a large central bore, anannular recess surrounding the bore and enlarged ears radially beyondsaid recess, associated with each slip ring; said recess including aradial surfaceparallel to said radial face; and a continuous ring brushdisposed between said vertical surface and said radial face ofcorresponding slip ring and brush holder; said ears including a centralbore therethru, a plurality of studs projecting horizontally from saidstationary frame thru said central bores to prevent rotation of saidbrush holders.

'7. In a slip ring arrangement for dynamo-electric machines including arotor shaft and rotor winding, a pair of generally circular brushholders spaced longitudinally on said shaft, each comprising an enlargedcenter opening surrounding the shaft, enlarged ears radially beyond saidbore, each ear including a central bore and a counterbore with ashoulder therebetween, one brush holder including an electrical inputterminal, the other brush holder including an electrical returnterminal, the central bore and counterbore of said one brush holderbeing larger than on said other brush holder, an insulating bushingincluding an internal shoulder and being symmetrical with said largerbore and counterbore inserted therein, the shoulder of the bushing onthe shoulder of said other brush holder being positioned in horizontallyaligned but opposed relationship; and a compression spring having oneend seated on each named shoulder urging said brush holders apart.

8. A slip ring arrangement for a dynamo-electric machine, including arotor shaft and rotor windings, comprising: grooves in the rotor shaft,a shoulder on the shaft, split cylindrical collars with an internalprojection and a tapered external circumferential surface installed onthe shaft so that one of said collar projections lies in one of saidgrooves, and another collar projection lies in a different groove,generally cylindrical slip rings with a tapered internal surface adaptedto engage corresponding tapers on said collars, a thin layer ofinsulating material separating said tapers but opening into one groovein the rotor shaft at the split section of the collars, leads positionedin the grooves for electrically connecting the slip rings with saidrotor windings, said leads attaching to said slip rings adjacent thesplit section of collars.

9. A slip ring arrangement for a dynamo-electric machine including arotor shaft and rotor windings, comprising: a shoulder on the shaft,split cylindrical collars secured against rotation on the shaft, saidcollars having an external taper, generally cylindrical slip rings witha tapered internal surface adapted to engage corresponding tapers onsaid collars, insulating material separating said tapers, an insulatingwasher surrounding the shaft and separating said slip rings axially, aspacer inserted between said shoulder and the adjacent collar, means forelectrically connecting said slip rings and said rotor windings, saidmeans passing thru said spacer, and fastening means associated with theshaft acting in cooperation with said shoulder to urge saidcorresponding tapers into binding engagement and to secure said collarsagainst axial displacement.

10. A slip ring arrangement for a dynamoelectric machine including arotor shaft, a winding on the shaft, slip rings spaced on the shaft andinsulated therefrom and. from each other but connected to opposite endsof the rotor winding, said slip rings having opposed radial faces,continuous ring brushes each having two sides, each brush receivingcurrent of a different polarity, one side of each having a radialsurface corresponding to said slip ring radial face, and spring meansassociated with the other side of said brushes for urging said radialface and said radial surface into engagement so that a continuous D. C.current will flow through the rotor winding.

11. A slip ring arrangement for dynamo-electric machines including arotor shaft, rotor windings and a stationary frame, comprisingdiametrically opposed grooves in said shaft, a shoulder on the shaft,threads on the shaft spaced axially from said shoulder, splitcylindrical collars surrounding said shaft between said threads andshoulder, said Collars including an internal projection diametricallyopposite the split therein, said projections engaging alternate groovesof external taper, vertical face slip rings including 7 an internaltaper engaging corresponding collar tapers but being separatedtherefrom, a thin cylinder of insulating material causing thisseparation, a pair of generally circular brush holders inserted betweenthe vertical faces of said slip rings, said brush holders includingprojecting ears with a bore and counterbore therein and each brushholder including an annular recess and terminal screws, said annularrecess of each brush holder opening toward the vertical face of itscorresponding slip ring, a continuous ring carbon brush inserted intosaid recess, said brush being split to assist installation, commonspring means associated with corresponding counterbores of the adjacentbrush holders to urge said brush holders and brushes into engagementwith the vertical faces of said slip rings, a lead positioned in eachgroove to electrically alternate slip rings with the rotor windings, andstuds associated with the stationary frame and said bores to preventrotation of the brush holders, insulating washers associated with onebrush holder to prevent a short circuit thru the studs.

12. A slip ring arrangement for a dynamo-electric machine including aframe and a rotor shaft, comprising slip rings on the shaft, a generallycircular brush holder surrounding the shaft and stationary with respectto the frame associated with each slip ring, an annular recess in brushholder, a continuous ring brush inserted in said recess, meansassociated with said brush holders to apply a force sufficient to movethe brush into cooperative engagement with both the brush holder andslip ring, but permitting relative creeping movement of the brush aroundthe shaft to distribute wear on the brush.

13. A slip ring arrangement for dynamo-electric machines including arotor shaft and rotor windings, comprising: a radial face slip ringsupported on the shaft, a brush holder spaced from said slip ring, andbrush means between said slip ring and said brush holder, said brushmeans contacting said slip ring throughout a major portion of saidradial face and free to move radially with respect to said slip ring.

14. A slip ring arrangement for dynamo-electric machines including arotor shaft and rotor Windings, comprising: aradial iace slip ringsupported on the shaft, a brush holder spaced from said slip ring andbrush means between said slip ring and said brush holder, said brushmeans contacting said slip ring throughout a major portion of saidradial face and being free to move with respect to both said slip ringand with respect to said brush holder.

15. The arrangement set forth in claim 13 in which said brush means isfree to move with respect to both said slip ring and with respect tosaid brush holder.

16. A dynamo-electric machine having a rotor, awinding on said rotorhaving a pair of terminals, a pair of slip rings mounted in spacedrelationship on said rotor with corresponding slip rings connected tocorresponding winding terminals,

each of said slip rings having a radial face, brush rings, each of saidbrush means contacting a corresponding slip ring throughout a majorportion of said radial face.

17. lihe arrangement set forth in claim 16 in which said brush means arefree to move both with respect to said brush holding means and withrespect to the corresponding slip ring.

18, A dynamo-electric machine having a rotor, a winding on said rotor,said winding having a pair of terminals, a pair of slip rings mounted inspaced relationship on said shaft, and each of said slip rings having aradial face, brush holding means spaced from said slip rings andpositioned therebetween; a plurality of brush means between, on the onehand, said brush holding means, and on the other hand, a correspondingone of said slip rings, each of said brush means contacting acorresponding slip ring throughout a major portion of said radial faceand being free to move with respect to both said brush holding means andwith respect to the corresponding slip ring.

ROBERT G. LE TOURNEAU. CHARLES C. ROE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Great Britain of 1907

